<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        ul{
            list-style: none;
        }
        #box{
            width: 70px;
            margin: 100px auto;
            background-color: #FCFCFC;
            text-align: center;
        }
        #box i{
            width: 70px;
            height: 45px;
            line-height: 45px;
            font-size: 14px;
            /* position: relative; */
        }
        #box ul{
            display: none;
        }
        #box li{
            width: 70px;
            height: 45px;
            line-height: 45px;
            font-size: 14px;
        }
    </style>
</head>
<body>
    <div id="box">
        <i>新浪&nbsp;
            <img src="./images/新浪箭头.png" alt="">
        </i>
        <ul>
            <li>私信</li>
            <li>评论</li>
            <li>@我</li>
        </ul>
    </div>
    <script>
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        var ul = document.querySelector('ul');
        i.onmouseover = function(){
            ul.style.display = 'block';
        }
        i.onmouseout = function(){
            ul.style.display = 'none';
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    </script>
</body>
</html>